The emergingbrown spots on the leaves of strawberriesmay have various forms, but in all cases they weaken the plant, inhibit its growth and deteriorate the quality of the crop. To enjoy he althy and delicious strawberries, find outwhere the brown stains on strawberry leaves come from , what strawberry diseases can contribute to this, andhow to get rid of brown stains from strawberry leavesHere are proven prevention methods and recommended sprays!
Brown spots on strawberry leaves
Fig. © PoradnikOgrodniczy.pl
Where do the brown stains on strawberry leaves come from?
One of the basic diseases that causes brown spots on strawberry leaves is the so-calledstrawberry leaf spot whiteIn this disease, spots of different sizes appear on the upper side of the leaf. Initially, they are brown, small and round, and with time they increase in size and become light gray with a brown-red border.Characteristic is the formation of a white (or light gray) mesh inside the spots
Warm and humid weather favors the development of the disease. Then the stains may take a rusty brown color. With a strong infectionthe spots cover the entire surface of the strawberry leaf , which consequently leads to its dieback. Sometimes, on the brown spots on the leaves of strawberries, there is an additional delicate bloom, consisting of clusters of the stems and conidial spores.
Another strawberry leaf disease that causes brown leaf stain isstrawberry red leaf spot The characteristic symptoms of the disease arenumerous, irregular, small, brown-purple spots that appear mostly on older, well-developed, outer leavesOver time, these leaves turn yellow, redden and die.
With fairly strong infectionsthe spots may merge and form reddish necroses with a gray discoloration in the middle part , which is somewhat reminiscent of the symptoms of white spot on strawberry leaves. However, we can see the difference by the spots appearing on the upper side of the leaf, dark, small, flattened elevations, which are the creations of the conidial stage of the fungus.
Another strawberry disease that manifests itself as irregular watery spots on the underside of the leaf between the veins isStrawberry angular bacterial blotchAs the disease progresses, the spots grow larger, blend together and become visible on the upper side as well the leaf. When the discoloration is numerous, the spots merge together along the main and lateral nerves. The tissues of the dead leaves break apart and the affected leaves look jaggedIf the brown spots on strawberry leaves are close to the main nerves, the disease spreads rapidly to other parts of the plant.
A characteristic disease of strawberries, which manifests itself in the last stage of infection in the form of brown spots on the leaves, is powdery mildew. The first symptoms of the disease can be observed in the form of a white-gray, powdery bloom developing mainly on the underside of the leaf.Infected strawberry leaves curl upwardsAfter the appearance of the main symptoms of powdery mildew, we observe gradual reddening of the edges and severe damage to the leaf blade. There are also brown spots on strawberry leaves, often the tissue dies in the place of discoloration.
How to prevent stains on strawberry leaves?
In the cultivation of strawberries on the plot, it is very important to take preventive measures that will help us eliminate or reduce the occurrence of diseases that contribute to the formation of brown spots on strawberry leaves in the first stage.
If we wantto prevent brown spots from appearing on the strawberry leaves :
- it is very important to fertilize, mulch, regularly weed strawberries,
- selection of disease-resistant strawberry varieties is extremely important,
- it is worth delaying the planting of strawberries (it is best to do them after October 15 or April 10), thanks to which we will reduce the risk of plant infection.
How to fight brown spots on strawberry leaves?
Usually,in the case of brown spots on the strawberry leaves , the above-mentioned preventive actions are not enough and it is necessary to spray them.
First of all, it is worth reaching for the biological preparation Polyversum WP , which can be used both prophylactically and after the appearance of stains on strawberry leaves. Polyversum WP is capable of combating both white and red strawberry leaf spot, as well as powdery mildew. It eliminates as many as 3 different causes of brown stains on strawberry leaves.At the same time, it is a preparation based on natural ingredients, characterized by high safety of use and no harm to the environment. Therefore, it is ideal for use in amateur garden strawberry cultivation.
The first spraying of Polyversum WP should be done in early spring , right after starting the vegetation. The next treatments should be performed every 7 days from the beginning of the flowering phase. Polyversum WP in strawberry cultivation is used in a dose of 1g per 3-6 liters of water, which is enough for spraying 100m² of the crop.
Good to know!
Polyversum WP has no grace period, which means that you can spray strawberries until the fruit is harvested.
Othereffective protection agents to combat brown spots on strawberry leavesare: Signum 33 WG, Topsin M 500 SC and Magnicur Gold. They help with white spot of strawberry leaves and powdery mildew.
We use Signum 33 WG twice during the growing season . The first treatment should be performed at the beginning of flowering (during the opening of the first buds), the second treatment should be performed in the fully flowering phase. Signum 33 WG is used at a dose of 18g / 100m² of cultivation.
" Spraying strawberries with Topsin M 500 SCis performed from the beginning of the inflorescence development (when flower buds appear at the bottom of the rosette) to the full flowering phase (open flowers of the second and third row, the first flowers fall) , before the development of fruit buds and after harvest.Possible spraying dates are given, but we must remember that Topsin M 500 SC is used only once per season. The most convenient term in amateur strawberry cultivation is the date after harvesting the fruit. Possible earlier spraying, i.e. during the flowering and fruit emergence phase, can be done with other preparations (preferably using the natural Polyversum WP so as not to spray the plants with chemicals, from which we will then eat the fruit).The recommended dosage of Topsin M 500 SC is 15 ml per 100 m2 of cultivation. "
Magnicur Gold is used in the period of the greatest risk of strawberry diseases , i.e. from the phase when most of the flowers with petals form a concave ball, to the phase of the beginning of fruit ripening (when they start to stain). The recommended dose is 2.5 g / 100m² of strawberry cultivation. With this agent, you can also spray a maximum of 2 during the growing season.
To improve the effectiveness, Signum 33 WG, Topsin M 500 SC and Magnicur Gold preparations should be used alternately, bearing in mind the grace period, i.e. the time that must pass from the last spraying to the day of harvesting the fruit. The most sensible way seems to be to apply the first spring spray with Signum 33 WG (at the beginning of strawberry flowering), and then use Magnicur Gold (no later than at the beginning of fruit ripening). After harvesting, you can spray Topsin M 500 SC.
"For people who avoid the use of chemicals in the garden, we recommend spraying with the natural Polyversum WP agent in the spring, until the fruit is harvested, and after harvesting one-time spraying of the strawberries with Topsin M 500 SC after harvesting them. More about this last spray can be found in the article on strawberry care after harvest.
MSc Eng. Joanna Białowąs
